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June 23, 2010 -- Botox injections may do more than smooth your wrinkles and limit your facial expressions. These popular injections may also dampen your ability to feel emotions. The study findings appear in the journal Emotions.

Botox injections were the No. 1 nonsurgical cosmetic procedure performed in 2009, according to statistics by the American Society for Aesthetic Plastic Surgery.

“For at least some emotions, if you take away some part of the facial expression, you take away some of the emotional experience,” says study researcher Joshua Ian Davis, PhD, a term assistant professor in the department of psychology at Barnard College in New York City.

“Whether this is a benefit or a detriment depends on your goals,” he says.

Botox Dampens Emotions

Botox injections smooth wrinkles by paralyzing the underlying muscles that cause the wrinkles. In the new study, participants who received Botox injections self-reported less emotional response to some emotional video clips, and as a result, did not feel their emotions quite as deeply as their counterparts who received treatment with a wrinkle filler called Restylane, which does not paralyze muscles. Instead, Restylane restores volume to facial folds and wrinkles.

This dampened emotional reaction was only related to mildly emotional clips, suggesting that the strength of the emotional impulse may make a difference.

That said, those who received Botox reacted to the same to video clips after their injection as they as they did before they received the injections.

The new research set out to prove the facial feedback hypothesis. This hypothesis suggests that our facial expressions can affect our emotional experience. There seems to be some merit to the hypothesis when the effects of Botox were compared with the effects of Restylane.

More research is needed to validate and expand upon this work, Davis tells WebMD.

“We have not had a chance to specifically isolate each muscle group and determine how they relate to specific emotions," he says. “The kinds of things that would be most interesting to follow up on is to try look more closely at specific emotions and specific muscles such as frown lines, crow’s feet, smile lines.”

Second Opinion

“It's interesting but very preliminary, and I would not make any significant conclusions from this data,” says Steven H. Dayan, MD, clinical assistant professor of facial plastic surgery the University of Illinois in Chicago.

“People who get Botox or other injectables do feel better about themselves and can make a better first impression,” he says. “There is evidence showing that a mild adjustment of face such as raising the brows with Botox can make a person look friendlier, happier or nicer, and if people look friendlier, happier, or nicer, they probably feel that way as well.”

Botox manufacturer Allergan Inc. says the media coverage of the new study has not been accurate so far.

“This study looked at the facial feedback hypothesis which surmises that creating a facial expression will increase intensity of emotional experience and conversely that preventing a facial expression will decrease emotional experience,” Allergan spokesperson Kellie Lao tells WebMD in an email. “There is no conclusive evidence in the medical literature that supports the hypothesis that preventing a facial expression will decrease emotional experience, and this study’s findings does not support the theory that facial expression is necessary to trigger an emotional experience."